显式定义关系实体时，不要忘记更改模型？

Question

在sdn5应用程序中使用下面的域类，我能够创建人员并将他们存储在neo4j中。从DB的角度来看，一切都还可以(存在节点和关系(。

import com.fasterxml.jackson.annotation.JsonIgnore
import com.fasterxml.jackson.annotation.JsonIgnoreProperties
import com.fasterxml.jackson.annotation.JsonProperty
import com.fasterxml.jackson.annotation.ObjectIdGenerators
import org.neo4j.ogm.annotation.*
@NodeEntity(label = "Person")
data class Person(
@Id
@GeneratedValue
private var id: Long?,
@Index
private var email: String,
@Property var firstName: String,
@Property var lastName: String,
@Property var photo: String,
@Relationship(type = "KNOWS", direction = Relationship.OUTGOING)
@JsonIgnoreProperties("outgoing")
private var knows: MutableList<Person>
) 
@RelationshipEntity(type = "KNOWS")
data class Knows(
@Id
@GeneratedValue
val id: Long?,
@StartNode
private var outgoing: Person,
@EndNode
private var incoming: Person
) 

但当我尝试获取实体时，NodeEntities的一切都很好，但对于具有的RelationshipEntities，一切都失败了

java.lang.NullPointerException: null
at org.neo4j.ogm.context.MappingContext.nativeId(MappingContext.java:498) ~[neo4j-ogm-core-3.1.0.jar:3.1.0]
at org.neo4j.ogm.context.MappingContext.remember(MappingContext.java:482) ~[neo4j-ogm-core-3.1.0.jar:3.1.0]
at org.neo4j.ogm.context.MappingContext.addRelationshipEntity(MappingContext.java:283) ~[neo4j-ogm-core-3.1.0.jar:3.1.0]
at org.neo4j.ogm.context.GraphEntityMapper.createRelationshipEntity(GraphEntityMapper.java:409) ~[neo4j-ogm-core-3.1.0.jar:3.1.0]
at org.neo4j.ogm.context.GraphEntityMapper.mapRelationshipEntity(GraphEntityMapper.java:351) ~[neo4j-ogm-core-3.1.0.jar:3.1.0]
at org.neo4j.ogm.context.GraphEntityMapper.mapRelationships(GraphEntityMapper.java:325) ~[neo4j-ogm-core-3.1.0.jar:3.1.0]
at org.neo4j.ogm.context.GraphEntityMapper.mapEntities(GraphEntityMapper.java:201) ~[neo4j-ogm-core-3.1.0.jar:3.1.0]
at org.neo4j.ogm.context.GraphEntityMapper.map(GraphEntityMapper.java:132) ~[neo4j-ogm-core-3.1.0.jar:3.1.0]
at org.neo4j.ogm.context.GraphEntityMapper.map(GraphEntityMapper.java:88) ~[neo4j-ogm-core-3.1.0.jar:3.1.0]

如果我删除RelationshipEntity的显式声明。。。一切正常。我已经用java类进行了测试。。。同样的问题。

我做错了什么？

提前感谢

Github中的完整测试用例Patrice

Answer 1

感谢Gerrit Meier(请参阅Github(，当您定义RelationshipEntity时，不要忘记从模型中引用它。在上面的例子中，我们需要写：

@NodeEntity(label = "Person")
data class Person(
@Id
@GeneratedValue
private var id: Long?,
@Index
private var email: String,
@Property var firstName: String,
@Property var lastName: String,
@Property var photo: String,
@Relationship(type = "KNOWS", direction = Relationship.OUTGOING)
@JsonIgnoreProperties("outgoing")
private var knows: MutableList<Knows>

希望这会有所帮助。